Background

Transparent gel from the pulp of the meaty leaves of Aloe vera has been used topically for thousands of years to treat wounds, skin infections, burns, and numerous other dermatologic conditions. Dried latex from the inner lining of the leaf has traditionally been used as an oral laxative.

There is strong scientific evidence in support of the laxative properties of aloe latex, based on the well-established cathartic properties of anthroquinone glycosides (found in aloe latex). However, aloe's therapeutic value compared with other approaches to constipation remains unclear.

There is promising preliminary support from laboratory, animal, and human studies that topical aloe gel has immunomodulatory properties that may improve wound healing and skin inflammation.

Evidence

DISCLAIMER:
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Constipation (laxative):
Dried latex from the inner lining of aloe leaves has been used traditionally as a laxative taken by mouth. Although few studies have been conducted to assess this effect of aloe in humans, the laxative properties of aloe components such as aloin are well supported by scientific evidence. A combination herbal remedy containing aloe was found to be an effective laxative, although it is not clear if this effect was due to aloe or to other ingredients in the product. Further study is needed to establish dosing and to compare the effectiveness and safety of aloe with other commonly used laxatives.
Grade: B

Genital herpes:
Limited evidence from human studies suggests that extract from Aloe vera in a hydrophilic cream may be an effective treatment of genital herpes in men (better than aloe gel or placebo). Additional research is needed in this area before a strong recommendation can be made.
Grade: B

Psoriasis vulgaris:
Early evidence suggests that an extract from aloe in a hydrophilic cream may be an effective treatment of psoriasis vulgaris. Additional research is needed in this area before a strong recommendation can be made.
Grade: B

Seborrheic dermatitis (seborrhea, dandruff):
Early study of aloe lotion suggests effectiveness for treating seborrheic dermatitis when applied to the skin. Further study is needed in this area before a strong recommendation can be made.
Grade: B

Cancer prevention:
There is early evidence that oral aloe may reduce the risk of developing lung cancer. Further study is needed in this area to clarify if it is aloe itself or other factors that may cause this benefit.
Grade: C

Canker sores (aphthous stomatitis):
There is weak evidence that treatment of recurrent aphthous ulcers of the mouth with aloe gel may reduce pain and increase the amount of time between the appearance of new ulcers. Further study is needed before a firm recommendation can be made.
Grade: C

Diabetes (type 2):
Study results are mixed. More research is needed to explore the effectiveness and safety of aloe in diabetics.
Grade: C

Dry skin:
Traditionally, aloe has been used as a moisturizer. Early low-quality studies suggest aloe may effectively reduce skin dryness. Higher quality studies are needed in this area.
Grade: C

HIV infection:
Without further human trials, the evidence cannot be considered convincing either in favor or against this use of aloe.
Grade: C

Lichen planus:
Limited study suggests that aloe may be a helpful, safe treatment for lichen planus, which is a chronic inflammatory disease that affects the lining of the mouth. Additional study is needed.
Grade: C

Skin burns:
Early evidence suggests that aloe may aid healing of mild to moderate skin burns. Further study is needed in this area.
Grade: C

Ulcerative colitis (including inflammatory bowel disease):
There is limited but promising research of the use of oral aloe vera in ulcerative colitis (UC), compared to placebo. It is not clear how aloe vera compares to other treatments used for UC.
Grade: C

Wound healing:
Study results of aloe on wound healing are mixed with some studies reporting positive results and others showing no benefit or potential worsening of the condition. Further study is needed, since wound healing is a popular use of topical aloe.
Grade: C

Mucositis:
There is early evidence that oral aloe vera does not prevent or improve mucositis (mouth sores) associated with radiation therapy.
Grade: D

Pressure ulcers:
Early well-designed studies in humans found no benefit of topical acemannan hydrogel (a component of aloe gel) in the treatment of pressure ulcers.
Grade: D

Radiation dermatitis:
Reports in the 1930s of topical aloe's beneficial effects on skin after radiation exposure lead to widespread use in skin products. Currently, aloe gel is sometimes recommended for skin irritation caused by prolonged exposure to radiation, although scientific evidence suggests a lack of benefit in this area.
Grade: D